US 4,682,750 A · Low profile extensible support platform

Abstract

Twin linkage assemblies shift a support platform between a low profile, fully collapsed position and a fully extended position of a height suitable for supporting a workman underneath an aircraft or for supporting, for instance, an engine at a comfortable working position. A hydraulic cylinder and piston assembly is connected at opposite ends to swivel members and torque arms, the latter of which are connected to short links which in turn are coupled to linkages interconnecting a base and the work supporting platform. The torque arms, in cooperation with the swivel members, facilitate swinging of the links and linkages to reduce the force necessary to separate the platform and base to a value smaller than would otherwise be required. In preferred embodiments, opposite end regions of the cylinder and piston are provided with trunnions that carry the swivel members and which engage stops mounted to the platform and base, to resist rotational urging of the piston and cylinder assembly and to assist the torque arms in swinging the links and associated linkages both when the assembly is collapsed and when the assembly is extended.

A low profile extensible support platform assembly comprising:

a base extending generally in a reference plane;
platform means extending generally in a plane substantially parallel to said reference plane and defining a work supporting surface;
a first pair of spaced linkages each pivotally connected to said base and shiftably coupled to said platform means;
a second pair of spaced linkages each pivotally connected to said platform means and shiftably connected to said base,
each of said first pair of linkages and each of said second pair of linkages being elongated and presenting an intermediate region;
a first pair of link means each pivotally coupled to said intermediate region of one of said first pair of linkages and each pivotally connected to said platform means;
a second pair of link means each pivotally coupled to said intermediate region of one of said second pair of linkages and each pivotally connected to said base,
said first pair of linkages during shifting movement along said platform means and said second pair of linkages during shifting movement along said base being swingable in an arc about said base and said platform means respectively for moving said platform means either toward or away from said base while retaining said platform means in substantially coplanar relationship with said base as said first pair of link means swings in an arc about said first pair of linkages and said platform means and as said second pair of link means swings in an arc about said second pair of linkages and said base;
extensible means having a first end portion and a second end portion selectively movable along an axis toward and away from said first end portion;
an elongated swivel member pivotally coupled to one of said end portions of said extensible means for swinging movement about the latter;
torque arm means pivotally interconnecting said swivel member and an adjacent pair of one of said first and second pairs of link means;
said torque arm means being positioned to exert a torque on an adjacent pair of said link means as said second end portion of said extensible means is moved away from said first end portion of said extensible means to exert tension on said swivel member and thereby said torque arms means, and to cause said first link means and said second link means to swing in an arc about said first pair of linkages and said second pair of linkages respectively;
and
stop means connected to one of said platform means and said base and engageable with one of said second end portion and said first end portion of said extensible means respectively for supporting said extensible means during engagement therewith and for opposing rotation of said extensible means about an axis transverse to its axis of extensible movement as said second end portion of said extensible means is moved away from said first end portion, to thereby simultaneously increase the tension on said swivel member and assist said torque arm means in exerting a torque on said adjacent pair of link means, and for simultaneously causing said first pair of linkages and said second pair of linkages to swing about said base and said platform means correspondingly to move said platform means away from said base as may be desired.

11 more elements

Low profile extensible support platform

Life of this patent

Low profile extensible support platform

Life of this patent

Abstract

Claims9